Around 200 games across nine countries have been implicated in the biggest match-fixing scandal to hit European football, with German police yesterday warning the cases they had so far uncovered were "only the tip of the iceberg".

Fifteen people were arrested in Germany and two in Switzerland following more than 50 raids across those two countries, Austria and Britain during which cash and property worth more than €1m (£900,000) was seized. At least 200 people, including 32 players, are suspected of being involved.

None of the affected matches were played in British leagues, or in France, Spain or Italy. Among the games believed to have been manipulated are three Champions League matches and 12 Europa League games, all in this year's early qualifying rounds. A qualifying match for the European Under-21 Championship is also under suspicion.

The most high-profile matches under suspicion took place in the top division of the Turkish League.

At a press conference in Bochum, Germany, that was broadcast on live TV prosecutors, police and Uefa officials revealed that organised criminal gangs had influenced players, referees, coaches and other match officials in order to make millions of euros on the betting markets.

The number of people involved is likely to be even higher because authorities say the number of affected games also could be higher according to Bochum's police director, Friedhelm Atlhans. "This is only the tip of the iceberg," he said.

Peter Limacher, Uefa's head of disciplinary services, said he believed it was the biggest match-fixing scandal to hit Europe. "We feel a certain satisfaction but on the other side we are deeply affected by the scope of game manipulations by international gangs," he said.

Limacher has been responsible for overseeing a new Uefa unit designed to target corruption and match fixing, monitoring betting markets to detect suspicious patterns. Uefa officials are believed to be shocked by the scale of the problem.

Uefa said this year that 40 matches in its own competitions were under suspicion and confirmed yesterday that the 15 named by German police were on that list. "Uefa will be demanding the harshest of sanctions before the competent courts for any individuals, clubs or officials who are implicated in this malpractice, be it under state or sports jurisdiction," said Uefa's general secretary, Gianni Infantino. The governing body's new monitoring unit has been co-operating with police to provide information on suspect betting patterns.

According to German authorities, 32 games are under suspicion in Germany, including four in the second division. The others were lower-tier matches.

In Belgium, 17 second division games are under suspicion; in Switzerland, 22 second division games; in Croatia, 14 first division games; in Slovenia, seven first division games; in Turkey, 29 first division games; in Hungary, 13 first division games; in Bosnia, eight first division games, and in Austria, 11 first and second-division games.

In 2005, the German referee Robert Hoyzer was convicted of fraud after admitting he had manipulated games.

In March Uefa announced a crackdown on corruption. It promised to work with national associations to fund a monitoring programme across 29,000 fixtures in the top two divisions of all 53 member countries as well as its own competitions.

Platini has made the fight against corruption a key priority of his presidency, telling Uefa's inaugural betting and integrity workshop in August that fixing matches "takes away their raison d'etre, deprives them of the magic of competition and is ultimately killing football".

Its new Betting Fraud Detection System, a sophisticated piece of monitoring software operated by a team of anti-corruption officers, has been in operation since the beginning of the season.